Copper coulometer


Copper coulometer
Copper coulometer

The copper coulometer is a one of the common application of the copper-copper(II) sulfate electrode. Such a coulometer consists of two identical copper electrodes immersed in slightly acidic pH-buffered solution of copper(II) sulfate. Passing of current through the element leads to the anodic dissolution of the metal on anode and simultaneous deposition of copper-ions on the cathode. These reactions have 100% efficiency over a wide range of the current densities.

Calculation

Amount of the quantity of electricity passed through the cell can be easily calculated by mass changes of any of the electrodes:

Q = \frac{ \Delta\ m*2*F}{63.546},

where:

  • Q is the quantity of electricity (coulombs)
  • \Delta\ m is the mass transported (gm)
  • 63.546 is the atomic weight of copper (the factor 2 is due to the transport of divalent ions)
  • F is the Faraday constant (96485.3383)

Although from a theoretical and historical point of view this apparatus is interesting, present day electronic measurement of time and electrical current provide in their multiplication the amount of passed coulombs much easier, with greater precission, and in a shorter period of time than is possible by weighing the electrodes.

See also

References


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Copper-copper(II) sulfate electrode — Diagram of an electrode used in the field The Copper copper(II) sulfate electrode is a reference electrode of the first kind[1], based on the redox reaction with participation of the metal (copper) and its salt copper(II) sulfate. It is used for… …   Wikipedia

  • Mercury coulometer — is an electroanalytical chemistry device using mercury to determine the amount of matter transformed (in coulombs) during the following reaction: Hg2+ + 2e– = Hgo[1] These oxidation/reduction processes have 100% efficiency with the wide range of… …   Wikipedia

  • Coulometry — is the name given to a group of techniques in analytical chemistry that determine the amount of matter transformed during an electrolysis reaction by measuring the amount of electricity (in coulombs) consumed or produced.[1] There are two basic… …   Wikipedia

  • Hofmann voltameter — A Hofmann voltameter is an apparatus for electrolyzing water, invented by August Wilhelm von Hofmann (1818–1892). It consists of three joined upright cylinders, usually glass. The inner cylinder is open at the top to allow addition of water and… …   Wikipedia